The Physiology of the Tunnel, Blackmore

download The Physiology of the Tunnel, Blackmore

of 14

Transcript of The Physiology of the Tunnel, Blackmore

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    1/14

    T h e h y s i o l o g y o f t h e T u n n e lS u s a n J B l a c k m o r eT o m S T r o s c ia n k oU niversi ty o f r i sto l

    A B S T R A C T S e v e r a l t h e o r i e s t o a c c o u n t fo r t h e o r i g in o f t u n n e l h a l l u ci n a -t i o n s a n d t u n n e l e x p e r i e n c e s n e a r d e a t h a r e c o n s i d e r e d : (1 ) t h e i d e a o f a r e a lt u n n e l ; (2 ) r e p r e s e n t a t i o n s o f t r a n s i t i o n ; (3 ) r e l i v i n g b i r t h m e m o r i e s ; (4 ) i m a g -i n a t i o n ; a n d (5 ) p h y s i o l o g i c a l o r ig i n s . T h r e e d i f f e r e n t p h y s i o l o g i c a l t h e o r i e s a r ec o n s i d e r e d t h a t r e l a t e t h e t u n n e l f o r m t o t h e s t r u c t u r e o f t h e v i s u a l c o r te x . A l lc a n a c c o u n t fo r m u c h o f t h e p h e n o m e n o l o g y o f t h e t u n n e l e x p e r ie n c e , a n d a l ll e a d t o t e s t a b l e p r e d ic t io n s . I t i s a r g u e d t h a t t h e t u n n e l e x p e r i e n c e i n v o l v e s ac h a n g e i n t h e m e n t a l m o d e l o f t h e s e l f i n t h e w o r ld . B e c a u s e o f t h i s , a ne x p e r i e n c e o f p u r e l y p h y s i o l o g i c a l o r i g i n , w i t h n o i m p l i c a t i o n s f o r o t h e r w o r l d so r f or s u r v i v a l, c a n n e v e r t h e l e s s p r o d u c e l a s t i n g c h a n g e s i n t h e s e n s e o f s e l fa n d r e d u c e t h e f e a r o f d e a t h .

    T h e t u n n e l i s d a rk . T h e l i g h t a t t h e e n d i s b r i g h t , b e a u t i f u l , a n da l l u r i n g . W e w a n t t o r e a c h t h e l i g h t . I t i s c o m i n g n e a r e r .

    T h e t u n n e l e x p e r i e n c e is e x c i t in g a n d s o m e h o w m y s t e r i o u s . I t g i v est h e i m p r e s s i o n o f m y s t e r i e s a b o u t t o b e s o lv e d o r s ec r e ts a b o u t t o ber e v e a l e d . A n d y e t i t s e e m s l i k e l y t h a t i t s o r i g i n l i e s i n t h e s t r u c t u r e o ft h e v i s u a l c o r t e x . W e s u g g e s t t h a t t h e s e t w o a s p e c t s a r e n o t i n c o m p a t -i b l e . W e s h a l l e x p l a i n p o s s i b le p h y s i o l o g i c a l o r i g i n s o f t h e t u n n e l a n de x p l o r e t h e r e a s o n s f o r i ts n u m i n o u s q u a l i t i e s .

    H e r e i s a n e x a m p l e o f a t u n n e l e x p e r i e n c e o c c u r r in g a s p a r t o f a n e a r -d e a t h e x p e r i e n c e (N D E ) . I t w a s r e p o r t e d t o u s b y a 7 0 - y e ar - o ld w i d o wa n d o c c u r r e d in 1 9 6 0 w h e n s h e w a s o p e r a t e d o n f o r a s p i n a l t u m o r .

    Dr. Blackmore and Dr. Troscianko are at the Perceptual Systems Research CentreD epartm ent o f Psychology, U nive rsity of Bristol. Requests fo r reprin ts should be ad-dressed to Dr. Blackmore at the D epartm ent of Psychology, U nive rsity of Bristol, 8-1 0Berk eley Square, Bristol B S8 1H H, England.

    Journal o f Near-Death Studies, 8(1) Fall 19 899 19 89 Human Sciences Press 5

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    2/14

    16 JOURNAL OF NEAR-DEATH STUDIES

    Suddenly amidst all this pain (I was still in the dark) I saw a lightvery faint and in the distance. It got nearer to me, and everything wasso quiet; it was warm, I was warm, and all the pain began to go. WhenI finally stood out of the dark, and into this light, it was the mostbeautiful thing I have ever seen: soft, warm, translucent. I was finallythere, and I felt as i f someone had put their arms around me. I wassafe, no more pain, nothing, just this lovely, caring sensation.Next thing I remembered was a doctor or somebody twisting mycheek and several people doing things to me.This happened again (I think once). Then my husband was againvisiting me with my children. I was only vaguely aware of them. Idrifted off. I could again see this light. I couldn t wait to go back downthat tunnel.

    T u n n e l a l lu c i n a t io n sAs early as 1905 Ernes t Dunb ar collected cases of tun nel experienced

    und er anesthetics and wit h oth er drugs (Dunbar, 1905). The tun nel isalso one of the form constants noted by Heinr ich Klu ver in the 1930s(Kluver, 1967). He claimed that almost all hallucinations, regardlessof th eir cause, took on similar basic forms. The four he listed were(1) grating, lattice, fretwork, filigree, honeycomb, or chessboard de-sign; (2) tun nel , funnel , alley, cone, or vessel; (3) spiral; and (4) cobweb.He also noted tha t t hese simple halluci nations were extrem ely brigh tand the colors highly saturated.

    These hallucinations can occur in widely different conditions fromhypnagogic image ry whe n falling asleep (Schachter, 1976); the aurasof epilepsy, migra ine, or insuli n h ypo glyc emia (Cowan, 1982); and withhallucinogenic drugs, such as LSD or mescaline (Siegel, 1977). Need-less to say, the t unn el also occurs as an impo rtan t part of the NDE(Moody, 1975; Ring, 1980). Inte rest ing ly, th e oth er forms do not. T heNDE seems to include tunnels, funnels, alleys, cones, and possiblyvessels. It also includes gr eat voids of blackne ss and space, but nograti ngs and cobwebs. The spiral, of course, may form a kind of tun nel ,but we have not come across any examples of a dying person passingthrough a cobweb or dancing on a chessboard.

    This provides an in teres ting question. Why is it the tu nne l alone th atseems to be so important in NDEs? Should we ignore this differenceand seek one explan ation for all the kinds of hallucination; should weassume that all the forms arise from similar causes and then seek toexpla in why NDEs do not include gratings and cobwebs; or should we seekentirely separate explanations for NDEs and other hallucinations, suchtha t NDEs provide a glimpse into anothe r world? We shall retu rn to thisquestion havin g considered some of the available evidence.

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    3/14

    SUSA N J. BLACKM ORE AND TOM S. TROSCIANKO 17

    K e v i n D r a b ( 19 8 1) s t u d i e d 7 1 t u n n e l e x p e r i e n c e s o b t a i n e d f r o m 1 , 1 12r e p o r t s o f u n u s u a l e x p e r i e n c e s . H e e x c l u d e d d e s c r i p t i o n s o f v o i d s a n db l a c k s p a c e s a n d d e f i n e d t h e t u n n e l a s t h e p e r c e p t i o n o f a r e a l i s t i ce n c l o s e d a r e a o f s p a c e m u c h l o n g e r t h a n i ts d i a m e t e r a n d fo u n de x a m p l e s o c c u r r i n g i n c a r d i o p u l m o n a r y a r r e st ; s e v e r e s tr e s s ( fr o md i s e a s e o r t r a u m a ) ; m i l d s t re s s ( in c l u d i n g m i n o r i n j u r ie s a n d p a i n ,f a t i g u e , fe a r , m i l d f e v e r o r t o x i c c o n d i t i o n s , a n d m i g r a in e s ) ; a n d n o r m a lc o n d i t io n s ( in c l u d i n g r e l a x a t i o n , s le e p , m e d i t a t i o n a n d h y p n o s is ). M a n y o ft h e l a t t e r c a t e g o r y w e r e a s s o c i a t e d w i t h o u t- o f- b od y e x p e r i e n c e s ( O B E s) .

    H e f o u nd , a m o n g o t h e r th i n g s , t h a t t h e t u n n e l w a s m o r e f r e q u e n t i ns e r i o u s m e d i c a l c o n d i t io n s t h a n i n n o n s e r i o u s c o n d it io n s . A l so , a s o n em i g h t e x p e ct , m a n y o f t h e s e r io u s c a s e s i n v o lv e d h e a r t a t t a c k s o rm e c h a n i c a l a c c i d e n ts . H o w e v e r , t h e r e w e r e n o c a s e s w i t h c a n c e r o rs t ro k e . S i n c e t h o s e t w o c o n d i t i o n s r a n k s e c o n d a n d t h i r d a m o n g t h el e a d i n g c a u s e s o f d e a t h i n A m e r i c a n s , t h i s i s s u r p r is i n g . I t i s a l sok n o w n t h a t p a t i e n t s w i t h c a n c e r do r e p o r t m o o d e l e v a t i o n s a n d v i s io n so f o t h e r w o r l d s (O s is & H a r a l d s s o n , 1 97 7). D r a b c o n c l u d e d t h a t t u n n e le x p e r i e n c e s a r e m o r e o f t e n t r i g g e r e d b y a s u d d e n c h a n g e i n p h y s io l o g i-c a l s t a t e s u c h a s a n a b r u p t d r o p i n b l o o d p r e s s u r e o r s h o ck .

    T h e t u n n e l s w e r e u s u a l l y d a r k o r d im l y l i t ( on ly 1 0% w e r e b r i g h t l yl it) , a n d n o n e o f t h e e x p e r i e n c e r s r e p o r t e d t o u c h i n g t h e s id e s , a l t h o u g ht h e s e v a r i e d w i d e l y a n d i n c l u d e d s c i n t i l l a t i n g d a r k n e s s , l u m i n o u sv a p o r w i t h f i n e l in e s , a n d b r i c k s w i t h a c o b b l e s t o n e f lo o r. B e f o r e m y(S B ) o w n f i r s t O B E I w e n t d o w n a t u n n e l m a d e o f l e a v e s ( B l a c k m o r e ,1 9 8 2a ) a n d I h a v e o f te n e x p e r ie n c e d t u n n e l s m a d e o f v a r y i n g t e x t u r e s ,b r i g h t l i g h ts , o r b a n d s o f d a r k e r a n d l i g h t e r g r a y .

    N e a r l y h a l f o f D r a b ' s c a s e s r e p o r t e d a l i g h t a t t h e e n d o f t h e t u n n e l .A n d 7 3 % o f t h o s e d e s c r i b e d i t a s b e c o m i n g l a r g e r i n t h e i r f ie l d o f v i s i o na n d d e s c r i b e d t h e m s e l v e s a s m o v i n g t o w a r d s i t . M a n y d e s c r i b e d t h el ig h t a s e x t r e m e l y b r i g h t a n d s o m e e v e n c o m m e n t e d t h a t i t d id n o ts e e m t o h u r t t h e i r e y e s . A l m o s t a l l o f D r a b ' s e x p e r i e n c e r s d e s c r ib e dm o v i n g t h r o u g h t h e i r t u n n e l s ; m o s t w e n t th r o u g h , s o m e u p , a n d s o m ed o w n , b u t o n l y e i g h t c a s e s d e s c r i b e d c o m i n g b a c k t h r o u g h t h e t u n n e l .I t is n o t c l e ar f r o m D r a b 's d e s c r ip t i o n w h e t h e r t h e y c a m e b a c k w a r d st h r o u g h t h e t u n n e l o r t u r n e d a r o u n d a n d m o v e d f o r w a r d s in th e o p po -s i t e d i r e c t i o n .

    x p l a i n i n g t h e T u n n e l x p e r i e n c eW h a t k i n d o f e x p l a n a t i o n a r e w e l o o k in g fo r? W e t h i n k w e n e e d t o

    a n s w e r t h i s b e f o r e c o n s i d e r i n g a n y o f f er e d e x p l a n a t i o n s . O u r o w np r i o r i t i e s a r e t h a t f i r s t t h e t h e o r y s h o u l d a c c o u n t w e l l f o r t h e p h e n o m e -

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    4/14

    18 JOURNAL OF NEAR-DEATH STUDIES

    nology. This means explaining why there is a tunnel and not some-th in g else, why it is like it is, why the re is a light at the end, and so on;and above all, why it seems so real. Second, the theory should notmult iply other worlds or bodies or vibrations ad hoc. Third, it shouldprovide testable predictions and the means for changing and improv-ing the theory by experiment. Applying these criteria means thatuntes table occult theories tha t can '~explain ever ythi ng but can neverbe refut ed are not helpful. No more helpful are dismissive theories ofthe k ind 'tit's all imag ina tio n or '~It's all in the mind. Of course, itmay all be in the mind, if tha t phrase means a nything, but this iscerta inly no explanation. So a successful theory mus t account for thephenomena in ways that are economical and testable.There are generally four types of explana tion offered for the tun nelexperience.

    A Real TunnelIn some occult systems there is said to be an actual t unn el th at leads

    from one world to the next.The problems with such theories are many. If the other worlds aresomehow part of this world, then we should be able to measur e t he m orin some way detect their presence. Attempts to do this have notablyfailed (Blackmore, 1982a). On the other hand, most exponents argueth at the hi gher worlds are in some other dimension or different plane.If these planes and dimensions are not com mensurate with t he physi-cal world the n all the problems of any bra in -min d dua lism are raised.How can an yt hi ng be said to pass from one world to anothe r? Positing atunnel between them certainly does not help. Such theories can nei-ther explain the phenomena, except in a purely ad hoc way, norprovide any predictions by which they might be tested or improved.

    Representation of TransitionAn alternative is to say that the t unne l is symbolic of the t ransit ion

    from one state of consciousness to another. Robert Crookall (1964)wrote th at the re are at least three ~deaths as first the physical, the nthe soul, and finally the spirit ual body are shed to unveil the Et ern alSelf. The t unne l is a bl acki ng out of consciousness as it passes from onesta te to another. Celia Green (1968) proposed the t un ne l as a represen-tat ion of a long journey an d K enn et h Ring (1980) considered the tun nel

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    5/14

    SUSAN J. BLACKMORE AND TOM S. TROSCIANKO 19

    a ps y c h o lo g i c al p h e n o m e n o n t h r o u g h w h i c h t h e m i n d s h if ts f ro m i t sn o r m a l s t a t e o f c o n s c i o u s n e s s to a h o l o g r a p h i c o r f o u r - d i m e n s i o n a lc o n s c i o u s n e s s o f p u r e f r e q u e n c i e s .

    T h i s i d e a e s c a p e s t h e o b v i o u s p r o b l e m s o f p o s i t i n g ~r ea l t u n n e l s a n da l l o w s f o r m o r e f l e x ib i l i ty . B u t i n t h e p r o c e s s w e s u g g e s t t h a t i t l os e sa l l p o w e r a s a n e x p l a n a t i o n . I t s im p l y b e g s t h e q u e s t i o n ~ 'W hy t h et u n n e l ? W h y s h o u l d n ' t s o m e t h i n g e l s e b e u s e d a s a s y m b o l o f t r a n si -t i o n ? T h e r e c o u l d b e g a t e s , d o o r w a y s , a r c h e s , c h a s m s , o r t h e g r e a t r i v e rS t y x . I n f a c t t h e s e o t h e r f o r m s d o o cc u r l a t e r o n in N D E s , i n t h e s t a g eo f w o r l d s b e y o n d , b u t i t is t h e t u n n e l t h a t a p p e a r s r e g u l a r l y , i n p r e d ic t -a b l e fo r m s , a n d , a s w e h a v e s e e n , i n n u m e r o u s d i f f e re n t c i r c u m s t a n c e s .W e u n d e r s t a n d t h i s u b i q u i t o u s t u n n e l n o b e t t e r b y s a y i n g t h a t i t i ss y m b o l i c o f s o m e t h i n g e ls e.

    R e l i v i n g i r t h M e m o r ie sO n e o f t h e m o s t p o p u l a r t h e o r i e s i s t h a t t h e N D E i s a r e l iv i n g o f o n e 's

    b i r t h a n d t h a t t h e t u n n e l i s r e a l l y t h e b i r t h c a n a l ( H o n e g g e r , 1 9 83 ;S a g a n , 1 97 7) . T h i s t h e o r y h a s b e e n r o u n d l y c r i t ic i z ed a l r e a d y ( B e c k e r,1 98 2). T h e m a i n p r o b l e m s a r e t h a t i t i s i m p l a u s i b l e t o s u p p o s e t h a t t h ei n f a n t w o u l d p e r c e i v e t h e w o r l d in a f o r m t h a t c o u l d l a t e r b e r e c a l le db y a n a d u l t w i t h t o t a l l y d i f f e r e n t p e r c e p t u a l c a p a b i l i t i e s . A l so t h eb i r t h c a n a l i s n o t h i n g l ik e a t u n n e l w i t h a li g h t a t t h e e n d , a n d i n a n yc a s e t h e f e t u s i s p u s h e d a l o n g i t w i t h t h e t o p o f i t s h e a d u s u a l l ye m e r g i n g f ir s t, n o t i t s ey e s . I t t a k e s a v a s t l e a p o f t h e i m a g i n a t i o n t om a k e t h e t w o c o m p a r a b l e , a n d y e t t h is t h e o r y h a s p r o d u c e d a w e l t e r ofN e w A g e i d e a s a n d t e c h n i q u e s .

    O n e v i r t u e o f t h i s k i n d o f t h e o r y i s th a t , a t l e a s t i n s o m e f o rm s , i t i st e s t a b l e . I f t h e t u n n e l e x p e r i e n c e i s r e l i v i n g b i r t h m e m o r i e s , t h e n t h ek i n d o f b i r t h s h o u l d m a k e a d i ff e re n c e . I n p a r t i c u l a r , p e o p l e b o r n b yC e s a r e a n s e c t io n h a v e n e v e r b e e n a l o n g t h e b i r t h c a n a l a n d s o , p r e -s u m a b l y , s h o u l d n o t b e a b l e t o r e l iv e i t . O n e o f u s c a r r i e d o u t a s u r v e yo f 2 5 4 p e o p le , o f w h o m 3 6 h a d b e e n b o r n b y c e s a r e a n s e c ti o n . T h e s e 3 6d i d n o t r e p o r t m o r e o r f e w e r t u n n e l e x p e r i e n c e s t h a n t h e o t h e r s ; 3 6 % ofe a c h g r o u p r e p o r t e d t u n n e l e x p e r i e n c e s ( B l a c k m o r e , 1 9 8 2 b) .

    T o c i r c u m v e n t t h i s d i ff ic u l ty , S c o t t R o g o ( 19 8 2) h a s a r g u e d t h a t t h et u n n e l i s n o t a c t u a l l y r e l i v i n g o n e ' s b i r t h b u t i s a k i n d o f s y m b o l i cr e p r e s e n t a t i o n o f b i r t h i n g e n e r a l . I n d e e d C a r l S a g a n ' s t h e o r y c a n b ei n t e r p r e t e d i n t h i s w a y . I f so , t h i s t h e o r y i s e q u i v a l e n t t o t h e p r e v i o u sk i n d o f t h e o r y a n d s u ff e rs f r o m t h e s a m e w e a k n e s s .

    R o g o d id , h o w e v e r , s u g g e s t t h a t p e o p l e w h o h a d a d i f fi c u lt b i r t h

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    6/14

    20 JOURN AL OF NEAR-DEATH STUDIES

    w o u l d h a v e m o r e n e g a t i v e a s s o c ia t io n s w i t h l a t e r O B E s t h a n p e o p lew h o h a d a n e a s y b ir t h . A s f a r a s w e k n o w t h i s h a s n o t y e t b e e n t e s te d .Imagination

    A l o t o f c o m m e n t a t o r s s e e m t o li k e th e i d e a t h a t t h e t u n n e l , t h e O B E ,a n d m a n y o t h e r e x p e r i e n c e s a r e ~ 'just i m a g i n a t i o n . W e r e f e r t o t h i sa p p r o a c h a s a d i s m i s s i v e n o n e x p l a n a t i o n ( B l a c k m o r e , 1 9 88 ). T h e e x p e -r i e n c e s a l m o s t c e r t a i n l y a r e , o r i n c lu d e , t h e i m a g i n a t i o n , b u t t h isa l o n e i s no e x p l a n a t i o n . I f s p ec if ic s i m i l a r i t i e s b e t w e e n i m a g i n a t i o na n d t h e t u n n e l e x p e r i e n c e c a n b e fo u n d , t h e n t h i s i s h e l p fu l , b u t w em u s t r e m e m b e r t h e c r i t e r i a f o r a u s e f u l t h e o r y . T h e ~'just i m a g i n a t i o nt h e o r y n e i t h e r a c c o u n ts fo r t h e p h e n o m e n o l o g y ( w h y t h e d a r k t u n n e lw i t h a l i g h t a t t h e e n d , a n d n o t a g r e e n g a t e w i t h a d i t c h i n f r o n t o f i t ,a n d s o o n ), n o r i s i t r e a l l y t e s t a b l e . I t c a n , w e s u p p o s e , b e r e f u t e d b y t h ed e m o n s t r a t i o n o f s o m e t h i n g e l se b e i n g i n v o l v ed , b u t i t c a n n o t b e im -p r o v e d o n b y p r o g r e s s i v e t e s t s o r p o s i t i v e p r e d i c t i o n s . I t i s , b y i t s v e r yn a t u r e , a c o n t e n t l e s s e x p l a n a t io n . F o r t h a t r e a s o n w e w a n t a t h e o r yt h a t , e v e n i f i t s a y s t h e t u n n e l i s i m a g i n a r y , e x p l a i n s w h y o n e sh o u l di m a g i n e t u n n e l s r a t h e r t h a n a n y t h i n g e l s e .

    Physiological xplanationsI f w e s u p p o se t h a t t h e h a l l u c i n a t o r y f o r m c o n s t a n ts a r e g e n e r a t e d b y

    s o m e p h y s i o l o g i c a l p ro c e s s , w h e r e s h o u l d w e l o o k f o r i t? T h e r e i s g o o dr e a s o n t o t h i n k t h e y a r e g e n e r a t e d i n t h e c o r t ex . F ir s t , a c c o r d in g t oC o w a n (1 9 82 ) t h e y d o n o t m o v e w i t h t h e e y e s a n d a r e t h e r e f o r e n o ta f t e r i m a g e s o r o t h e r r e t i n a l e f fe c ts . S e c o nd , t h e y c a n b e p r o d u c e d b yp r e s s u r e o n t h e e y e s . I n th i s c a s e t h e y d o m o v e w i t h t h e e y e s b u t c a no n l y b e p r o d u c e d b y b i n o c u l a r p r e s s u r e , w h i c h a g a i n p o i n t s to t h ec o r t e x a s t h e s i te o f o r ig i n. T h e r e a r e n o w a n u m b e r o f t h e o r i e s t h a tr e l a t e t h e t u n n e l f o r m to t h e s t r u c t u r e o f t h e v i s u a l c o r te x .

    J o h n C o w a n (1 98 2) a r g u e d t h a t b e c a u s e w e k n o w t h e a p p e a r a n c e o ft h e h a l l u c in a t i o n s a n d a ls o t h e w a y i m a g e s o n t h e r e t i n a a r e m a p p e do n t o t h e c o r t e x (D a n i e l & W h i t t e r i d g e , 1 9 61 ), w e s h o u l d b e a b l e toc a l c u l a t e t h e c o r t i c a l f o r m t h a t c o r r e s p o n d s to a n y h a l l u c i n a t io n .U s i n g t h i s m a p p i n g h e s h o w e d t h a t c o n c e n t r i c r i n g s o n t h e r e t i n a o r i nt h e v i s u a l w o r l d c o r r e s p o n d to s t r a i g h t l i n e s p a r a l l e l t o o n e a x i s in t h ev i s u a l c o r te x . S t r a i g h t l i n es a t r i g h t a n g l e s to t h o s e a r e m a p p e d i n t h ev i s u a l c o r t e x a s r a d i a t i n g l in e s ; s t r a i g h t l i n es a t o t h e r a n g l e s a r e

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    7/14

    SUSAN J. BLACKM OREAND TOM S. TROSCIANKO 21

    m a p p e d a s s p ir a ls . I f t h e l i n e s m o v e , th e s p i r a ls o r r i n g s e x p a n d a n dc o n t r a c t. E x p a n d i n g c o n c e n t r ic r in g s c o u l d p r o d u c e t h e i m p r e s s i o n o fm o v i n g t h r o u g h a t u n n e l .

    B u t w h y s h o u l d t h e r e b e m o v i n g s t r i p e s a c r o s s t h e v i s u a l c o r t e x ?C o w a n o f fe r ed a n a n a l o g y w i t h t h e r m o d y n a m i c s . I n i t s n o r m a l s t a b les t a t e , c o rt ic a l a c t iv i t y i s i n h i b i t e d b y m a n y i n h i b i t o r y n e u r o n s . W h e nt h e s e n e u r o n s a r e d i s r u p te d , a s t h e y a r e k n o w n t o b e b y d r u g s s u c h a sL S D a n d b y a n o x i a , t h e d i s i n h i b i ti o n d e s t a b i l iz e s t h e u n i f o r m s t a t e ,a n d s t r ip e s o f a c t i v i t y p a s s a c r o s s t h e c o rt ex . T h e a n a l o g y i s w i t h af l u id h e a t e d f r o m b e lo w , i n w h i c h e i t h e r h e x a g o n a l p a t t e r n s o r s t r ip e so f r i s in g a n d f a l l i n g f l u id a r e p r o d u c e d . C o w a n c o n c l u d e d t h a t a s im i -l a r p r o c e s s ta k e s p l a c e i n t h e c o r t e x a n d g i v e s r i s e t o t h e f o u r fo r mc o n s t a n t s .

    T h i s t h e o r y s e e m s t o h a v e s o m e p r o b l e m s . F i r s t , i t d o e s n o t a c c o u n tf o r t h e f a c t t h a t N D E s i n c l u d e t u n n e l s b u t n o t c o b w e b s a n d l a t t ic e s . I td o e s n o t e x p l a i n w h y p e o p le s e e m t o m o v e f o r w a r d s t h r o u g h t u n n e l sb u t r a r e l y b a c k w a r d s . N o r d o e s i t e x p la i n j u s t w h a t t h o s e s t r i p e s a r ea n d w h y a n d h o w t h e y m o v e a s t h e y d o .

    O n e o f u s (S B ) t h e r e f o r e s u g g e s t e d a f a r s i m p l e r t h e o r y . P e r h a p s n os t r ip e s a r e n e e d e d a t a l l. W h e n t h e b r a i n i s s t a r v e d o f o x y g e n , i nh i bi -t i o n i s f i r s t s u p p r e s s e d , w h i c h c r e a t e s a s t a t e o f h y p e r a c t i v i t y . T h e c e ll si n t h e v i s u a l c o r t e x w i l l b e f ir i n g r a n d o m l y , o r n o i si ly . U s i n g t h e s a m er e t i n o c o r t ic a l m a p p i n g , w e c a n s e e t h a t t h e r e w i l l b e f a r m o r e c e ll sf i r in g t h a t r e p r e s e n t t h e c e n t e r o f t h e v i s u a l f i el d a n d f a r f e w e r a t t h ee d g e s . T h e e f f e c t w i l l a p p e a r l i k e a f l i c k e r i n g s p e c k l e d w o r l d t h a t g e t sb r i g h t e r a n d b r i g h t e r t o w a r d s t h e c e n t e r . I t is k n o w n t h a t t h e v i s u a ls y s t e m is b i a s e d t o w a r d s m o v e m e n t s i n a n o u t w a r d d i re c t i o n ( G eo rg e-s o n a n d H a r r i s , 1 97 8). I n a d d i t io n , v i s u a l l y p e r c e i v e d m o v e m e n t , e s p e -c i a l ly i n t h e a b s e n c e o f a n y r e f e re n c e , i s e a s i l y i n t e r p r e t e d a s s e l fm o v e m e n t ; t h e c l a ss ic e x a m p l e o f t h i s i s t h e f e e l i n g t h a t y o u r t r a i n i sm o v i n g b a c k w a r d s w h e n a n o t h e r t r a i n p u l ls o u t o f t h e s t a ti o n . I n o t h e rw o r d s , t h i s s c i n t i l l a t i n g s p e c k l e d w o r l d o f e l e c t ri c a l n o i s e c o u l d a p p e a rt o e x p a n d o u t w a r d s f r o m a b r ig h t e r c e n te r . C o u l d th i s b e th e t u n n e l ?

    T o m T r o s c i a n k o t h e n m a d e a f u r t h e r s u g g e s t i o n ( B l a c k m o r e T r os -c i a n k o , 1 98 8). P e r h a p s t h i s p r o c e s s w o u l d n o t b e e n o u g h t o p r o d u c e t h et u n n e l e ff ec t . H o w e v e r , i f y o u s t a r t e d w i t h v e r y l i t t le n o i s e a n d i tg r a d u a l l y i n c r e a s e d , t h e e f fe c t w o u l d b e o f a l i g h t a t t h e c e n t e r g e t t i n gb i g g e r a n d b i g g e r a n d h e n c e c l o s e r a n d c l o se r . T h e t u n n e l w o u l d o c cu ra s t h e n o i s e le v e l s i n c r e a s e d a n d w o u l d st o p e i t h e r w h e n t h e y d e -c r e a s e d a g a i n o r w h e n t h e w h o l e c o r te x w a s s o n o i sy t h a t t h e l i g h te n v e l o p e d i t al l. I n o t h e r w o r d s , o n e w o u l d h a v e e n t e r e d t h e l ig h t . I tc o u l d g e t n o b r i g h t e r .

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    8/14

    22 JOURNAL OF NEAR DEATH STUDIES

    A l l t h e s e t h e o r i e s h a v e s o m e a d v a n t a g e s i n c o m m o n . T h e y e x p l a i nw h y t h e r e i s a t u n n e l r a t h e r t h a n a n y o t h e r s y m b o l of p a s s a g e t oa n o t h e r w o r ld . T h e y e x p l a i n h o w t h e l i g h t c a n b e e x t r e m e l y b r i g h t b u td o e s n o t h u r t t h e e y e s: t h e e y e s a r e n o t i n v o l v e d a t a ll . T h e s t i m u l a t i o ni n t h e c o r t e x m a y b e a s b r i g h t , o r e v e n b r i g h t e r , t h a n a n y r e a l s t i m u l a -t i o n c o u l d a c t u a l l y p r o d u c e . T h e y a l l e x p l a i n D r a b s f i n d i n g s t h a t t h et u n n e l o c c u rs w i t h m o r e s e r i o u s m e d i c a l c o n d it io n s , a n d t h a t i t d o e sn o t o c c u r w i t h s l o w p r o g r e s s i v e d i s e a s e .

    r e d i c t i o n s f r o m t h e T h e o r i e sA l l th e p h y s i o l o g i c a l t h e o r i e s p r o v i d e t e s t a b l e p r e d ic t io n s . F o r e x a m -

    p le , t h e y i m p l y t h a t a n i n t a c t v i s u a l c o r t e x is r e q u i r e d , a n d i f t h i s w e r ed a m a g e d , a s in s o m e k i n d s o f b l i n d n e s s o r s t ro k e , t h e n t h e t u n n e l c o u l dn o t b e p r o d u c e d .

    I n o t h e r w a y s t h e y d if fe r . P r i m a r i l y , C o w a n s t h e o r y r e q u i r e s t h a tt h e r e b e s t r ip e s o f a c t i v i t y p a s s i n g a c r o s s t h e c o rt e x. T h i s m i g h t b er e l a t e d t o c o r ti c a l s p r e a d i n g d e p r e s s io n , w h i c h i s t h o u g h t t o b e i m p l i-c a t e d i n m i g r a i n e . T h i s s p r e a d s a t a r a t e o f 2 t o 3 m m p e r m i n ( L e a o,1 94 4). B y c o n t r a s t , C o w a n c l a i m e d t h a t t u n n e l h a l l u c i n a t i o n s f il l u pt h e v i s u a l f i e ld i n a b o u t 2 .5 m s e c , c o r re s p o n d i n g t o a p r o p a g a t i o nv e l o c i t y o f 1 o r 2 c m p e r s e c . H o w e v e r , h e g a v e n o d a t a o r r e f e r e n c e f o rh i s c la i m , a n d t h a t i s c l e a r l y s o m e t h i n g t o b e i n v e s t i g a t e d f u r t h e r .W h e t h e r o r n o t th e m e c h a n i s m i s s i m i l a r t o c o r ti c a l s p r e a d i n g d e p r es -s io n , i t w o u l d b e e x p e c t e d t o h a v e a r a t e d e p e n d e n t o n t h e n e u r a lm e c h a n i s m s u n d e r l y i n g i t. I n t h i s c a s e, w e s h o u l d e x p e c t , a c c o r d in g t oC o w a n s th e o r y , t h a t t h e t u n n e l w o u l d a l w a y s b e t r a v e l l e d a t r o u g h l yt h e s a m e s p e ed . T h i s a p p e a r s n o t t o b e t h e c a s e . S o m e p e o p l e c la i m t of l o a t g e n t l y d o w n t u n n e l s , w h i l e o t h e r s r u s h a t a t r e m e n d o u s r a t e .D r a b ( 19 8 1) r e p o r t e d 6 7 c a s e s d e s c r i b i n g m o v e m e n t , o f w h i c h 1 2 s a i dt h e y w e r e m o v i n g a t a s lo w t o m o d e r a t e s p e e d a n d 2 4 w e r e m o v i n gv e r y f a s t .

    B y c o m p a r i so n , B l a c k m o r e s t h e o r y m a k e s n o s t i p u la t i o n a b o u ts p e ed . I f t h e m o v e m e n t i s in d u c e d m e r e l y b y th e s p e c k l y n o i se , t h e n i td e p e n d s o n t h e a m o u n t o f n o is e : t h e m o r e n o i se , t h e g r e a t e r t h e s p e ed .B u t t h i s i n t u r n i m p l ie s t h a t f a s t e r m o v e m e n t i s a s s o c ia t e d w i t h al a r g e r c e n t r a l w h i t e a r e a . A s f a r a s w e k n o w , t h i s h a s n o t b e e n t e s te d .T h e f i n a l t h e o r y m a k e s a c le a r p re d i c ti o n . I f t h e m o v e m e n t i s c r e a t e db y t h e e x p a n s i o n o f t h e c e n t r a l w h i t e a r e a , t h e n s p e e d is n o t r e s tr i c te d ,b u t t h e o v e r a l l c h a n g e i n t h e t u n n e l is . I n o t h e r w o r d s , y o u c a n o n l ym o v e fr o m a t i n y w h i t e l i g h t t o a c o m p l e t e l y e n v e l o p i n g o n e . T h e f a s t e r

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    9/14

    SUSA N J. BLACKM ORE AND TOM S. TROSCIANKO 23

    y o u m o v e t h r o u g h t h e t u n n e l , t h e q u i c k e r t h e e x p e r i e n c e w i l l e n d . T h i sa l so h a s n o t b e e n t e s t e d . S o t h e s e d i f f er e n c e s p r o v i d e a w a y o f t e s t i n gt h e v a r i o u s t h e o r i e s , w h i c h c o u l d b e d o n e b y c o l le c t in g a p p r o p r i a t ed e s c r i p t io n s f r o m p e o p l e w h o h a v e e x p e r i e n c e d t h e t u n n e l .

    T h e r e a r e o t h e r p r e d i c t io n s m a d e b y th e s e t h e o r i e s . I f t h e k e y t o t h et u n n e l i s c o r t ic a l d i s i n h ib i t io n , t h e n t h e d r u g s t h a t p r o d u c e t u n n e l ss h o u l d a l l b e t h o s e t h a t r e d u c e i n h i b i t io n . T h i s c e r t a i n l y a p p e a r s t o b et h e c a s e , t h e m a j o r h a l l u c i n o g e n s b e i n g t h e b e s t e x a m p l e . O n t h e o t h e rh a n d , s o m e d r u g s i n c r e a s e i n h i b i t i o n , s u c h a s t h e m i n o r t r a n q u i l i z e r sl ik e V a l i u m , w h i c h a c t b y p o t e n t i a t i n g t h e n e u r o t r a n s m i t t e r g a m m a -a m i n o b u t y r i c a c id . W e s h o u l d t h e r e f o r e n o t e x p e c t t o f i n d t u n n e l e x p e-r i e n c e s i n p e o p l e t a k i n g t h e s e d r u g s . I n p a r t i c u l a r , i f t h e y a p p r o a c hd e a t h b y a n o v e r d os e o f s u c h d r u g s t h e y s h o u ld n o t h a v e t h e t ra d i -t i o n a l n e a r - d e a t h t u n n e l . A g a i n , t h i s p r e d i c t i o n h a s n o t b e e n te s t e d .

    W e w o u l d l ik e n o w t o r e t u r n t o t h e q u e s t i o n o f w h y t u n n e l s o c c urw h e n t h e y d o . W i t h t h e m a j o r h a ll u c in o g e n i c d r u g s t u n n e l s a r e c om -m o n , b u t s o a r e l a t t i c e s , s p i r a l s , c o b w e b s , a n d o t h e r s i m p l e f o rm s . T h et u n n e l s e e m s to h a v e a s p e c i a l p l a c e in t h e N D E . W h y i s t h i s?

    A s f a r a s w e c a n t e ll , C o w a n s t h e o r y p r o v i d e s n o a n s w e r . I f t h ed i s i n h i b i t i o n i s t h e s a m e r e g a r d l e s s o f i ts i m m e d i a t e c a u s e , t h e n t h ep a t t e r n s p r o d u c e d sh o u l d b e t h e s a m e . O n t h e o t h e r h a n d , b o t h t h eo t h e r t h e o r i e s c a n o n l y p r o d u c e t u n n e l f o rm s , a n d n o t t h e o t h e r f o r mc o n s t a n t s . I n p a r t ic u l a r , T r o s c i a n k o s t h e o r y s u g g e s t s t h a t t h e t u n n e lc a n o n l y o c c u r w h e n t h e r e i s a f a i r l y r a p i d i n c r e a s e i n c o r t ic a l n o i se , a sw o u l d b e e x p e c te d i n c a r d i o p u l m o n a r y f a i lu r e o r a n a c c id e n t o r s u d d e ns e v e r e s t r e s s .

    I n a d d i t io n , a l l t h e s e t h e o r i e s c a n a c c o u n t f or D r a b s a p p a r e n t l y o d df i n d in g t h a t t h e r e w e r e n o t u n n e l s r e p o r t e d b y s t ro k e v i c t i m s . T h e y a l lr e q u i r e a n i n t a c t v i s u a l c o rt ex , a n d i f t h a t w e r e d a m a g e d b y a s t r o k et h e t u n n e l c o u l d n o t b e s ee n . A f u r t h e r p r e d i c t i o n i s r e l a t e d t o t h is . I ft h e t u n n e l i s o f c o r t ic a l o ri g in , t h e n a n y o n e w i t h a d a m a g e d v i s u a lc o r t e x s h o u l d n o t e x p e r i e n c e i t. S o , f o r e x a m p l e , p e o p l e b l i n d t h r o u g hr e t i n a l d i s e a s e o r o t h e r d a m a g e i n t h e e y e s h o u l d h a v e t u n n e l e x p e ri -e n c e s j u s t l i k e a n y o n e e l se , b u t t h o s e s u f f e r i n g f ro m c o r ti c a l b l i n d n e s ss h o u l d n o t . T h i s t o o a w a i t s t e s t i n g .

    T h e f i r s t w a y t o t e s t t h e s e t h e o r ie s s h o u ld b e t o f i n d o u t j u s t w h a tk i n d o f v i s u a l s t i m u l a t i o n i s n e c e s s a r y t o i n d u c e t h e i m p r e s s i o n o fm o v i n g t h r o u g h a t u n n e l . O b v i o u s ly , w e c a n n o t o p e n u p s o m e o n e sc o r te x a n d a p p l y t h e h y p o t h e s i z e d s t im u l a t i o n t h a t w a y . W e c an ,h o w e v e r , m i m i c t h a t s t i m u l a t i o n b y p r e s e n t i n g v i s u a l f o rm s t o p e o pl e .U s i n g r e t i n o co r t ic a l m a p p i n g w e c a n c o n s t r u c t t h e v i s u a l e q u i v a l e n t o ft h e d i f f e re n t k i n d s o f c o r t i c a l s t i m u l a t i o n . I n C o w a n s c a s e t h i s w o u l d

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    10/14

    24 JOURN AL OF NEAR-DEATHSTUDIES

    b e c o n c e n t r i c r i n g s o r sp i r a l s. I n B l a c k m o r e ' s c a s e i t w o u l d b e r a n -d o m l y f l i c k e ri n g s p e c k s o f l i g h t d i s t r i b u t e d l i k e t h e c e ll s in t h e v i s u a ls y s te m , w i t h m a n y i n th e c e n t e r a n d f e w e r t o w a r d s t h e p e r i p h e ry . I nT r o s c i a n k o 's c a s e i t w o u l d m e a n h a v i n g b r i g h t n e s s a t a n y s p o t sc a l e da c c o r d in g to t h e s a m e m a p p i n g , w i t h t h e b r i g h t e s t i n t h e c e n t e r f a d i n go u t to t h e e d g e s , a n d t h e b r i g h t n e s s o f t h e w h o l e p i c tu r e g r a d u a l l yi n c r e a s i n g .

    S o f a r w e h a v e o n l y t r i e d t h e l a t te r . T r o s c i a n k o a n d h i s c o l l e a g u e sw r o t e a p r o g r a m t o d i s p l a y t h i s o n a m o n i t o r a n d i t d o e s i n d e e d a p p e a rl i k e a t u n n e l w i t h a b r i g h t l i g h t a t t h e e n d t h a t g e t s g r a d u a l l y b r i g h t e r( a n d a p p a r e n t l y n e a r e r ) ( B l a c k m o r e & T r o s c i a n k o , 1 9 88 ). T h i s re -s e a r c h i s s t i l l u n d e r w a y , a n d t h e n e x t s t a g e i s t o p r o d u c e th e o t h e rf o rm s a n d t o g e t p e o p le w h o h a v e h a d t u n n e l e x p e r ie n c e s t o c o m p a r et h e m w i t h t h e i r e x p e r i e n c e d tu n n e l s . T h i s m i g h t g i ve s om e f u r th e rc l u e a s t o t h e p r e c i s e o r i g i n o f t h e t u n n e l .

    I t c a n b e s e e n t h a t t h e s e p h y s i o l o g i c a l a p p r o a c h e s t o t h e t u n n e le x p e r ie n c e a l r e a d y a c c o u n t f o r m a n y o f t h e p r e v i o u s f in d in g s , a n d t h e yp r o v id e n u m e r o u s w a y s o f t e s t in g t h e m f or t h e f u t u r e . I n t h i s r e s p e c tt h e y a r e q u i t e d i f f e r e n t f r o m a l l t h e p r e v i o u s t h e o r i e s I h a v ec o n s i d e r e d .

    W h y I s t h e T u n n e l S o R e a lT h i s i s a q u e s t i o n m o s t p h y s io l o g i c a l t h e o r i e s l e a v e u n t o u c h e d . N e v -

    e r t h e l e s s , t h e e x p e r i e n c e c a n n o t b e fu l l y u n d e r s t o o d w i t h o u t c o n s id e r -i n g i t .W h e n t u n n e l s a p p e a r i n d r u g - i n d u c e d s t a te s , t h e y a r e u s u a l l y c o n si d-e r e d t o b e h a l l u c i n a t o r y o r i l l u s o r y (S i e g el , 19 7 7) ; b u t n e a r d e a t h , a n di n s o m e o t h e r O B E s , th e y s e e m t o b e a s r e a l a s a n y t h i n g i n n o r m a lp e r c e p t io n . W h y ? T o a n s w e r t h i s w e h a v e t o s t e p b a c k t o t h e q u e s t i o no f w h y a n y t h i n g e v e r s e e m s r e a l. I t s e e m s i m p l a u s i b l e t o s u p p o se t h a tt h e p e r c e p t u a l s y s t e m c a n e a s i ly d i sc r i m i n a t e i n p u t f r o m r e c a l le di n f o rm a t i o n w h e n t h e t w o a r e m i x e d a l m o s t f r o m t h e v e r y p e r ip h e r y .T h e r e f o r e t h e s y s t e m m u s t , a t s o m e l e ve l , m a k e a d ec i s i o n a b o u t w h i c ho f i t s r e p r e s e n t a t i o n s , o r m e n t a l m o d e l s , a r e ~ re a l a n d w h i c h i m a g i n -a r y . W e s u g g e s t t h a t i t d o e s t h i s a t a h i g h l ev e l, c o m p a r i n g r e p r e s e n t a -t i o n s o f t h e w o r l d a n d c h o o s in g t h e m o s t s t a b l e a s t h e o u t s i d e w o r ld ;i .e . a t t r i b u t i n g r e a l i t y t o i t ( B l a c k m o r e , 1 9 8 4 , 1 98 8) .N o r m a l l y , o f c o u r se , t h e m o d e l c h o s e n i s t h a t w h i c h i s c o n s t r u c t e d o nt h e b a s i s o f i n p u t . T h i s i s t h e o n l y o n e t h a t i s s t a b l e a n d p r e d i c t s f u t u r e

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    11/14

    SUSAN J. BLACKMOREAND TOM S. TROSCIANKO 25

    input as it goes along. Other models, by comparison, are fleeting andunstable. However, the conditions th at give rise to tunn el experiences,as well as OBEs, are precisely those in which input is disrupted, eitherbecause of dama ge to the nervous syste m or because of deep relaxat ion,medita tion, or sensory isolation. In these conditions the input model isno longer the most stable, an d therefore, according to my hypothesis,whichever model is most stable will take over as '~reality.

    If there is noise in the visual cortex producing a tunn el form, and ifthe input-driven model is also unstable, then the tunnel form will bethe most s table model in the sys tem an d hence will be chosen as '~real.This is why tunnels near death, but not in the milder drug-inducedexperiences, seem real. Indeed they are '~real in ju st th e same sense asanything ever is real; because they are the most stable model thesystem has at the time.

    We would take one further step from this, although it is not neces-sary to underst andin g the tunnel experience. That is to say tha t thesemental models are not something w e c o n s t r u c t Rat he r ~we are themen tal models constructed by the brain. One of us has argue d else-where (Blackmore, 1989) that consciousness is simply what it is likebeing a ment al model, and the sense of a separate self arises from theconst ruct ion of a model of a se para te self. In other words, the wholesyst em produces a mass of models, and we are just one of them. Thenorm al state of consciousness is dom inate d by a stable model of self inthe world. In the tunnel experience, the tunnel replaces the model ofthe outside world. It does not necessarily obliterate the model of self.

    However, when the tun nel occurs as part of the NDE, it m ay alsoinvolve the dissolution of the self model.

    W h y t h e S e n s e o f M y s te r yMore th an 80 year s ago Dunbar gave a marvelous account of the

    effects of anesthetics, which were th en prim aril y ether and chloroform.He wrote first:

    I have made a point of asking patients in the surgical wards how theyfelt when they were being anaesthetised. The common experience(eighty per cent of cases) is that of rushing into a dark tunnel. There issinging in the ears and a flashing of lights in the eyes. (Dunbar, 1905,p. 75)

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    12/14

    26 JOURNAL OF NEAR-DEATH STUDIES

    He also described experiments with ether:Next comes the sensation that the body is just as much a part of theenvironment as anything else, and it is perhaps this sensation which,together with the wide-awake intelligence, compels the individual toadopt the standpoint of subjective idealism; which, in its turn, driveshim to think that at last the solution of the mystery is dawning uponhim. (p. 73)

    Isn't this how it is in some drug experiences, in OBEs, and neardeath? In these states it seems as though the mystery is less impene-trable than before.This may not be mere delusion. Rather, given what we have saidabout mental models and consciousness, we think something quiteimport ant has happened. Our usual assumption, th at the input-basedmodel is a tr ue picture of a ~real world ~out ther e and tha t we are aseparate individual inhabiting that world and our bodies, is chal-lenged. It becomes obvious tha t there are other w ays of being aware.Any model can seem real. Our assumptions about the real world areshaken. It is this, we suggest, that gives rise both to the impressionth at ~the light is dawning and to the aftereffects of the experiences onpeople's lives.

    It is misleading tha t this metaphorical light is often equated with thephysiologically induced light. The light at th e end of the tun nel isinduced by randomly firing neurons. It is not jus t imaginat ion. It has avery definite physiological origin. This is no reason, however, to dis-miss t he often claimed insights as worthless. The physiologically in-duced tunn el can be one way of realizing somet hing impor tant aboutourselves, a realizati on th at can change our lives: tha t is, th at we aremental models and nothing more. Frightening as this is to our sobereveryday selves, it is not the least frightening when directly experi-enced. The extent to which this insight can be main tain ed when theexperience is over may be the exte nt to which fear of death is reduced.Finall y, we have hint ed th at the dissolution of the self model ispossible. All this mean s is tha t a biological sys tem th at is designed tobuild a model of self ceases to do so. It isn't an easy state to achieve.Strong biological pressures are against it, but it can happen eitherthrough long years of trai ning or in extremis Afterwards the selfmodel appears again. It is hard for ~you (the self model) to remem berwhat it was like not being; so these states are not easily recalled.Nevertheless there can be a lasting effect on the system. The self neverseems quite so solid again and the idea of its death is not so frightening.

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    13/14

    SUSAN J. BLACKMORE AND TOM S. TROSCIANKO 27

    C o n c l u s i o nW e h a v e p r e s e n t e d s e v e r a l t h e o r i e s o f t h e t u n n e l e x p e r ie n c e . T h ev a r i o u s p h y s i o lo g i c a l t h e o r i e s s e e m b y f a r t h e b e s t a b l e t o e x p l a i n t h e

    p h en om en o l og y o f t h e ex p er i en ce , t o p rov i d e t e s t ab l e p red i c t i on s , an dt o con t r i b u t e t o ou r u n d ers t an d i n g o f a l t ered s t a t e s o f con s c i ou s n es s . Ag r e a t d e a l o f w o r k n o w n e e d s t o b e d o n e t o d e t e r m i n e w h i c h , i f a n y , o fthese i s correct .

    T h es e t h eor i e s en t a i l n o o t h er wor l d s an d h o l d ou t n o h op e f ors u r v i v a l o f d e a t h . N e v e r t h e l e s s , f a r f r o m d e n i g r a t in g t h e t u n n e l e x p e -r i e n c e , w e t h i n k t h e y p r o v i d e a s t e p p i n g s t o n e t o u n d e r s t a n d i n g i t sn u m i n ou s an d l i f e - ch an g i n g q u a l i t i e s .

    A c k n o w l e g e m e n t sT om T ros c i an k o was f u n d ed b y t h e M ed i ca l Res ea rch Cou n c i l UK) .

    W e t h a n k P a t r ic k B o u g a n t a n d M a r n i S t e w a r t f or p r o g r a m m i n gas s i s t an ce .

    R e f e r e n c e sBecker, C.B. (1982). The failure of Saganomics: Why bir th models cannot explain near-death phenomena. Anabios i s: The Jou rna l o f Near-Death S tud i es 2 102-109.Blackmore, S.J. (1982a). Beyo nd the Body . London, England: Heinemann.Blackmore, S.J. (1982b). Birth and the OBE: An unhelpful analogy. J o u r n a l o f t h eAm eric an Socie ty for Psychical Research 77 229-238.Blackmore, S.J. (1984). A psychological theory of the out-of-body experience. J o u r n a l o fParapsychology 48 201-218.Blackmore, S.J. (1988). Out of the body? In Basil, R. (Ed.), No t Necessar il y t he New A ge:Crit ical Essays (pp. 165-184). Buffalo, NY: Prometheus Books.Blackmore, S.J. (1989). Consciousness: Science tackles the self. N ew Scienti st 12238-41.Blackmore, S.J., and Troscianko, T.S. (1988). The psychophysics of death. Perception 17419.Cowan, J.D. (1982). Spontaneous symmetry breaking in large scale nervous activity.In t erna t iona l Jou rna l o f Qu antu m Chemistry 22 1059-1082.Crookall, R. (1964). The Techniques o f As t ra l Projec tion: Den ouem ent a f t e r F i f t y Years.Northamptonshire, England: Aquarian Press.Daniel, P.M., Whitteridge, D. (1961). The representation of the visual field on thecerebral cortex in monkeys. Jou rna l o f Physiology 159 203-221.Drab, K.J. (1981). The tunnel experience: Reality or hallucination? Anabios i s : TheJou rna l o f Near -Death S tud i es 1 126-152.Dunbar, E. (1905). The l ight thrown on psychological processes by the action of drugs.Proceed ings o f the Socie ty for Psychical Research 19 62-77.

  • 8/13/2019 The Physiology of the Tunnel, Blackmore

    14/14

    2 8 J O U R N A L O F N E A R - D E A T H S T U D I E S

    Ge o rg e s o n , M.A . , H a r r i s , M.G . (19 78 ). A p p a re n t f e v e o fu g a l d r i f t o f c o u n te rp h a s eg r a t i n g s . Perception, 7, 5 2 7 -5 3 6 .Green , C .E . (1968) . Out-of-the-Body Experiences. L o n d o n , E n g l a n d : H a m i s h H a m i l t o n .Ho n e g g e r , B . (19 83 ). T h e OB E a s a n e a r -b i r th e x p e r i e n c e . In R o l l, W.G . , B e lo ff , J . , a n dWhite , R .A. (Eds . ) , Research in Parapsychology 1982 (pp . 230-231) . Metuchen , NJ :S c a re c ro w P re s s .K luv er , H . (1967) . Mescal an d M echa nism s o f Hal lucinatiora C h i c a go , I L : U n i v e r s i t y o fC h ic a g o P re s s .L e a o , A .A .P . (1 94 4) . S p re a d in g d e p re s s io n o f a c t iv i ty in th e c e re b ra l c o r t e x . J o u r n a l o fNeurop hysiology, 7, 359-390 .Moody, R.A. (1975). Li fe After Li fe. C o v in g to n , GA: Mo c k in g b i rd .Os is , K. , H ara l dsso n , E . (1977). A t t he Hour o f Death . N e w Y o r k , N Y : A v o n .Ring, K. (1980). Life at Death. N e w Y o r k , N Y : C o w a r d , M c C a n n G e o g h e g a n .Rogo , D.S. (1982) . Psycho log ica l mode ls o f th e ou t-o f-body ex per ien ce . Jou rna l o f Para-psychology, 46, 2 9 -4 5 .Sagan, C. (1977). Broca s B ra in N e w Y o r k , N Y : R a n d o m H o u s e .S c h a c h te r , D .L . (19 76 ). T h e h y p n a g o g ic s t a t e : A c r i t i c a l r e v ie w o f th e l i t e r a tu r e . Psycho.logical Bullet in, 83, 4 5 2 -4 8 1 .S ie g e l , R .K . (1 97 7) . Ha l lu c in a t io n s . Scient i f ic American, 237, 132-140 .